In certain existing satellite communication systems, the satellite terminal, during its initial installation and commissioning, performs a procedure, subsequently referred to as a ranging procedure, to determine the nominal transmit power setting for the uplink transmission. This nominal transmit power depends on the nominal value of end-to-end channel gain and the total noise plus interference level (the greater the channel gain, the lesser the required transmit power. On the contrary, the greater the noise and interference, the greater the required transmit power).
During the ranging, the satellite terminal transmits the ranging signal at one frequency. Based on a received power level or Signal to Noise Ratio (SNR) level of the ranging signal received at the satellite gateway, the satellite terminal determines a nominal transmit power level.
In certain existing satellite communication systems, spectral density, or level, of noise plus interference is assumed to be identical across all frequencies. The certain existing satellite communication systems assume that the spectral density is flat across all inroute frequencies. As a result, the nominal transmit power level estimated at the ranging frequency is used with respect to other inroute frequencies.